ST. LOUIS — Nearly 400 Missouri pastors gathered at the podium of a hotel ballroom recently to pray over the kneeling figure of Rep. Todd Akin, a Senate candidate whose campaign had been pronounced dead by national Republican leaders weeks before.

Akin’s political revival has become a cause celebre for this group of clerics and other conservatives, who have launched a carefully orchestrated effort to lift the GOP candidate back into contention for a seat that could help decide control of the Senate.